Winter sowing seems to have gained popularity in gardening climates where we have a short growing season, thanks to colder winter months.

For those that don’t know, winter sowing is the planting of seeds within covered containers (such as milk jugs), to start the growing process sooner. The containers create a mini “greenhouse”, providing a warmer environment for the seeds to grow.
There are several advantages to winter sowing:
- You get to plant seeds earlier. This is appealing to every gardener that is itching to get growing.
- The plants are more vigorous. Because they grow in a cooler environment (than indoors) and have the bright sun, they grow stronger and less leggy.
- Saves time with less watering (mother nature handles most of that), and no hardening off process since the plants are already outside (no hauling in and out).
Another huge benefit of winter sowing is that by starting your seeds outside in containers, you are freeing up indoor space for starting the more tender seeds that will not thrive as well as more cold hardy plants. This means MORE PLANTS!
PLANTS THAT WINTER SOW WELL
We’ve pulled together a list of plants from our research that are great candidates for winter sowing in zone 3 or 4:
Annuals:
- Alyssum
- Borage
- Calendula
- Clarkia
- Cleome
- Cosmos
-
Marigolds
- Nasturtiums
- Poppies
- Snapdragons
- Sweet Peas
- Sunflowers
- Violas
- Wallflowers
- Zinnias
Vegetables:
- Beets
- Beans
- Broccoli
- Brussel Sprouts
- Cabbage
- Cauliflower
- Kale
- Lettuce
- Bok Choy
- Rutabega
- Spinach
- Swiss Chard
- Squash
- Turnips
Perennials & Biennials:
-
Bachelor’s Buttons
- Delphinium
- Evening Primrose
- Echinecea
- Flax
- Foxglove
- Hollyhock
- Lupines
- Milkweed
- Monkshood
- Pasque Flower
- Prairie Coneflower
- Poppies
- Rubeckia
- Bee Balm
- Borage
- Lavender
- Catnip
- Chamomile
- Yarrow
Herbs:
PLANTS TO AVOID
With winter sowing, there are some plants that can be downright impossible, or very difficult to grow using the winter sowing method. If you think of plants that love heat and cannot be outside before your last frost date, these are typically not good candidates for winter sowing in zone 3 – 4:
- Cucumbers
- Melons
- Peppers
- Squash & Zucchinis
- Tomatoes
- Any vegetable with 100+ days to maturity
TIMING IS KEY
The best time to winter sow is at least a few weeks (if not sooner) before the last frost date. In our Calgary area, we get warm "Chinooks" which can wake up winter sown seeds, so we try to avoid planting close to a Chinook and waiting until closer to last frost. Mid February to early March is a good time for our area.
EXTRA SUPPORT
If you are curious about learning more about winter sowing, there are a ton of videos on YouTube, including this one and this one that we love from Franki-Lou Fuller.
I always love asking other gardeners what works for them. If you need extra help, consider joining a winter sowing Facebook group! Here are a couple I like:
- Winter sowing & Planting (Alberta Saskatchewan Manitoba)
- Winter Sowing & Growing In Northern Climates
- Wintersown Group
Happy sowing!